Synonyms: 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, diazotized, coupled with diazotized 2-((4-aminophenyl)amino)-5-nitrobenzenesulfonic acid, diazotized 2-chloro-4-nitrobenzenamine and 5,5'-((5-hydroxy-1,3-phenylene)bis(oxy))bis(1,3-benzenediol), sodium salt